From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1F6EEECDE20 for ; Wed, 11 Sep 2019 14:37:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E0B8221479 for ; Wed, 11 Sep 2019 14:37:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568212668; bh=1fczKAAqSGjDH9qf3eCyH0kGN2ggp27wOT47W+oQbtE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=EO4dYEKKwca+632pV6XYcVQCd6GClcKCSmuj54bYJFPbVo93Ilj7pt0i+wwuVZkYd phXEiS2ahULzn1rK2DL0Zj3VSBmyGyfiCEeBRd6g8OA8NXQ77vNtQwvGDnjGO30b/j EbZtxTSBAYqgZMDYnSj7ulYbwfh8eS0yeFO3Eb/c= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728090AbfIKOhr (ORCPT ); Wed, 11 Sep 2019 10:37:47 -0400 Received: from mail.kernel.org ([198.145.29.99]:40042 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726381AbfIKOhq (ORCPT ); Wed, 11 Sep 2019 10:37:46 -0400 Received: from X1 (110.8.30.213.rev.vodafone.pt [213.30.8.110]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C90A32053B; Wed, 11 Sep 2019 14:37:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568212664; bh=1fczKAAqSGjDH9qf3eCyH0kGN2ggp27wOT47W+oQbtE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=nWlWY+dAVzcqLF6822O67BEu6DZSELxK0ypBc4Thosu+kucgLcO/tbHvMQv81D6dm r/i7x3BEXb/FmQm3o2lQ8QiBxKF2to5xds4voBkuA268lJwuR0CzcoA/E2mWA2b1sO RloOpE8n4Y45ROxaZKYW4XFD7YyrWCYo1cQG5Y7k= Date: Wed, 11 Sep 2019 07:37:40 -0700 From: Andrew Morton To: Michal Hocko Cc: Shakeel Butt , Johannes Weiner , Vladimir Davydov , LKML , Linux MM , Andrey Ryabinin , Thomas Lindroth , Tetsuo Handa Subject: Re: [PATCH] memcg, kmem: do not fail __GFP_NOFAIL charges Message-Id: <20190911073740.b5c40cd47ea845884e25e265@linux-foundation.org> In-Reply-To: <20190911120002.GQ4023@dhcp22.suse.cz> References: <31131c2d-a936-8bbf-e58d-a3baaa457340@gmail.com> <20190906125608.32129-1-mhocko@kernel.org> <20190909112245.GH27159@dhcp22.suse.cz> <20190911120002.GQ4023@dhcp22.suse.cz> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 11 Sep 2019 14:00:02 +0200 Michal Hocko wrote: > On Mon 09-09-19 13:22:45, Michal Hocko wrote: > > On Fri 06-09-19 11:24:55, Shakeel Butt wrote: > [...] > > > I wonder what has changed since > > > . > > > > I have completely forgot about that one. It seems that we have just > > repeated the same discussion again. This time we have a poor user who > > actually enabled the kmem limit. > > > > I guess there was no real objection to the change back then. The primary > > discussion revolved around the fact that the accounting will stay broken > > even when this particular part was fixed. Considering this leads to easy > > to trigger crash (with the limit enabled) then I guess we should just > > make it less broken and backport to stable trees and have a serious > > discussion about discontinuing of the limit. Start by simply failing to > > set any limit in the current upstream kernels. > > Any more concerns/objections to the patch? I can add a reference to your > earlier post Shakeel if you want or to credit you the way you prefer. > > Also are there any objections to start deprecating process of kmem > limit? I would see it in two stages > - 1st warn in the kernel log > pr_warn("kmem.limit_in_bytes is deprecated and will be removed. > "Please report your usecase to linux-mm@kvack.org if you " > "depend on this functionality." pr_warn_once() :) > - 2nd fail any write to kmem.limit_in_bytes > - 3rd remove the control file completely Sounds good to me.